Pretensioner, seat belt retractor, and seat belt apparatus provided with the seat belt retractor

Abstract

Provided is a pretensioner that can be easily and accurately assembled and manufactured, a seat belt retractor, and a seat belt apparatus provided with the seat belt retractor. A pretensioner has at least a gas generator for generating gas in the event of an emergency, a case, a pipe mounted to the case, a predetermined number of drive transmission members that are movably provided in the pipe and moved by receiving gas pressure to transmit force for rotating the spool in the seat-belt retracting direction, a piston that is movably provided in the pipe and moved by receiving gas pressure to push the drive transmission members, a ring gear that is at least rotatably provided in the case, has, on the outer periphery thereof, a plurality of pressed portions pressed by the drive transmission members, and rotates the spool by the pressing force, and an elastic member attached to the gas generator side of the piston.

Dependencies are inferred from the claim text.